Conventional navigation-grade inertial sensors, such as quartz accelerometers, fiber optical gyroscopes and laser gyroscopes, are relatively expensive, large in size, and heavy in power consumption. These factors prevent their wide-spread use in many military and commercial applications. In contrast, a micro-electro-mechanical system (MEMS) navigation-grade inertial sensor, such as a MEMS gyroscope or accelerometer, is relatively inexpensive, much smaller in size, and consumes less power. Accordingly, it is feasible to build an inertial apparatus using multiple MEMS inertial sensors for many military and commercial applications.
A MEMS inertial sensor includes three dominating error components that combine to determine the overall accuracy of the sensor: (1) uncorrelated white noise, (2) a random constant bias, and (3) a temperature related bias. In light of these sources of error, one method of attempting to improve accuracy is to use the summation of the simultaneously digitized output of a concomitant sensor array, as described in U.S. Pat. No. 7,650,238 to Reynolds, et al., entitled “Environmental Characteristics Determination.” However, the methods described therein only reduce the uncorrelated white noise among the sensors. The correlated error due to the environmental changes is not reduced in this manner. Additionally, the methods described therein use as many analog to digital converters (ADCs) as the number of sensors, which make the implementation costly and the printed circuit board assembly (PCBA) relatively large.